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NAEP Analysis and Scaling → Estimation of Population and Student Group Distributions → Examining the Population-Structure Models Used in NAEP → Proportion of Variance Accounted For by Principal Components Used in NAEP Population-Structure Models → Proportion of Variance of the Group-Defining Contrasts Accounted for by the Principal Components Used in the Population-Structure Model, Grade 4 Reading Combined National and State Assessments: 2011

NAEP Technical DocumentationProportion of variance of the group-defining contrasts accounted for by the principal components used in the population-structure model, grade 4 reading combined national and state assessments: 2011
Type of contrast Number of contrasts Mean Minimum Maximum Number of contrasts by proportion1 of variance explained
0.00 - 0.70 0.70 - 0.80 0.80 - 0.90 0.90 - 0.95 0.95 - 1.00
1 (Total Variance – Residual Variance)/Total Variance, where Total Variance consists of both sampling and measurement error variance.
NOTE: NIES = National Indian Education Study; SD/ELL = Students with disabilities/English language learners.
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2011 Reading Assessment.
All contrasts 1816 0.90 0.63 1.00 12 90 716 604 394
Student questionnaire 48 0.90 0.72 0.99 0 8 9 11 20
Major reporting variables 212 0.92 0.67 1.00 2 3 54 85 68
Interactions between reporting variables 275 0.89 0.63 0.98 7 15 99 110 44
Teacher questionnaire 521 0.91 0.71 0.99 0 23 179 164 155
School questionnaire 421 0.90 0.75 0.99 0 8 203 158 52
NIES questionnaire 297 0.87 0.68 0.99 3 31 159 68 36
SD/ELL questionnaire 42 0.92 0.77 1.00 0 2 13 8 19

Last updated 24 February 2016 (GF)